A noise removal method employing multiresolution transform is widely used in a noise removal device that removes noise signals included in an image signal. In multiresolution transform, an image signal is divided into signals in a plurality of subbands using a filter bank or a Laplacian pyramid method, and therefore noise removal processing can be performed at an intensity suited to each of the divided bands during noise removal.
JP9-212623A discloses noise reduction processing employing a wavelet transform as a multiresolution transform method. Here, the wavelet transform is implemented on source image data to obtain a plurality of subbands components, whereupon noise reduction processing is implemented by performing coring processing on each subband component. The subband components after the coring processing are then resynthesized through an inverse wavelet transform, and as a result, noise reduction-processed image data are obtained.